Air conditioning apparatus



March 25,1958 L. E. DONAHUE AIR connmoumc APPARATUS Filed Aug. 1 1955 "-JWENTbRL A LAWREVQE' g; IDONAHLE LY I ATTORNEY AIR CONDXTHUNING APPARATUS Lawrence E. Donahue, Des Plaines, 11L, assignor to Minneapolis-Honeywell Regulator Company, Minneapolis, Minn, a corporation of Delaware Application August 1, 1955, Serial No. 525,705

14 Claims. (Cl. 236-13) This invention relates to air conditioning apparatus and more particularly to apparatus designed to control conditioning mediums are controllably mixed and delivered to a space to be air conditioned have previously been used in air conditioning apparatus, but such units have generally taken the form of blender boxes which are located at or in the space to be air conditioned. These units have been of the self-contained type and are operated to control both temperature and volume of the air delivered.

The subject invention is directed primarily to a simplified duct structure including air conditioned flow controlling means and associated control apparatus which operate as a self-contained unit to control both the volurne delivered air and the temperature of the delivered air. This unit may be attached to existing duct structures in which the controlling medium is supplied from a central conditioner and will supply the properly mixed and controlled amount of air conditioning medium to a duct leading to the space to be air conditioned in a simple.

compact unit which does not require location in the space to be air conditioned.

It is therefore an object of this invention to provide a simplified air conditioned and distributing apparatus.

It is also an object of this invention to provide a simplified and improved air conditioned flow apparatus or valve in a duct structure.

It is further an object of this invention to provide a simplified and improved control apparatus for a selfcontained air distributing unit.

These and other objects of this invention will become States Patent apparent from a reading of the attached description together with the drawings wherein:

Figure 1 is a schematic view of our improved air distributing apparatus;

Figure 2 is a section view of the apparatus of Figure 1 through the valve to disclose the details of the same;

Figure 3 is a plan view of an improved air pressure sensor for the distributing apparatus; and

Figure 4 is a second embodiment of the pressure sensor of our improved air distributing apparatus.

As it will be seen in Figure 1, our improved 'air distributing apparatus is comprised of a generally Y-shaped duct structure unit generally indicated at having a pair of inlet portions 11 and 12 located in the bifurcated portion of the duct structure and a common outlet portion indicated at 13. The inlet portions of the duct structure are adapted to be connected to trunk lines of an air conditioning structure indicated at 14 and 15, respectively, which trunk lines carry the air conditioning medium from a centrally located heat exchange or exchangers. Similarly the output portion of the duct structure 13 is adapted to be connected through suitable means such as a duct and grill 16 to discharge into the space to be air conditioned.

Positioned in the portions of the duct structure 11 and 12 are a pair of flow control means which are best shown in Figure 2 as comprising a centrally located V-shaped weir section 20 attached at its extremities to the walls of the duct structure and extending transversely thereof.

Positioned to either side of the V-shaped or wedged shaped weir member is an aperture in the duct structure over which is positioned a circular flexible diaphragm indicated at 21 and 22 respectively in Figure 2. The diaphragms are held in position over the apertures by means of a semi-spherically shaped cover member indicated at 23 and 24, respectively, which are suitably se' cured to the duct structure by screw means indicated at 25 and 26, respectively, which screw means together with the clamping of the cover hold the diaphragms in place over the apertures such that they may cooperate with the weir to control the flow of. air conditioning medium through the respective portions of the duct structure.

The space between the cover members 23 and 24 and the diaphragms 21 and 22 provide two chambers on the back sides of the diaphragms into which a portion of the air conditioning medium in the duct structure will be fed for the purpose of operating the diaphragms. As is indicated in Figure 2, a conduit or pipe extends through an aperture in the leading face of the weir, the conduit extending out of the duct structure and having a restriction indicated at 31 therein with branch paths indicated at 33 and 34, respectively, which lead to the respective chambers of the diaphragms, positioned in the inlet portions 12 of the duct structure.

It will be appreciated that the valve or flow control. mechanism positioned in the inlet portion 11 of the.

duct structure is identical in detail to that shown in Figure 2 for the inlet portion 12. Thus the centrally located weir has a pair of diaphragms associated therewith of which a part of diaphragm 42, and diaphragm 43 is shown in Figure 1 for the upper diaphragm of this flow control unit and a cover member 44 associated therewith to provide an upper chamber with a similar construction on the under side of the duct structure and cooperating with the weir 40. The weir has a centrallylocated conduit associated therewith having a restriction 51 therein with the conduit connected by means of branch pipes 52 and 53 which lead to the upper and lower chambers behind the diaphragms to provide a passage for.

the portion of the air conditioning medium to one side of the diaphragms to urge the diaphragms against the. weir and control the flow of the air conditioning medium through the inlet portion 11 of the duct structure. This valve unit is also held in assembly relationship with the covers (only one of which is shown) secured to the duct structure by suitable means such as screws 55.

As shown in Figure l, the conduit 30 for the flow coning of the controller. A centrally located diaphragm. '66 forms a pair of chambers with the diaphragms 63 and 64 with the diaphragm 63 having a nozzle associated therewith common to the conduit 30. Also positioned within thecasing 65 and against the diaphragm 63 is a spring means indicated at 67 which cooperates with they diaphragm to position the same with respect to the nozzle and control the pressure in the conduit 30 and hence in the chambers behind the diaphragms 21 and 22 of the flow Patented Mar. 25, 1958 control meansfor conduit or inlet portion not the duct 7 structure. The areas within the casing 65 and to either side of the diaphragms 63 and 64 on the opposite sides of the chambers formed by the diaphragms 63, 64 and 66 are vented to the atmosphere as indicated by the vents 69 and 70. similarlylthe diaphragms- 63, 64 and 66. are connected together by a suitable shaft or pin indicated at 73 such that the resultant movement caused by a pressure differentialand the resultant force from the spring 67 willbe imparted to the diaphragm 63 tocontrol its position in respect to the noz'zle on the conduit 30 to control the air bleed from and against the pressure within the chambers. In Figure l the chamber formed by the diaphragms 63 and 66- is' connected through a conduit 75 to an impact ressure sensor located in the output portion of the condu'i't 13. Similarly the chamber formed by the diaphragms 64 .and'66 is connected by means of a conduit 76 to a static pressure sensor positioned in the duct portion 13 of the duct structure. These two pressures sense or provide a signal proportional to total flow of the air'conditioning medium through the outlet portion of the duct structure'to maintain a constant volume of discharge of the air conditioning medium to the space to be air conditioned. Also included on the case 65 is an adjusting knob 77 which is connected through suitable linkages indicated at 78 to the spring 67 within the case to adjust the control point of the relay 60. The details of the velocity sensing portion or pick=up portion for the relay'will be best seen in the embodiments s'hown'in Figures 3 and 4. It should be noted that theiactual controller 60 is largely conventional in nature and is shown schematically for simplicity purposes.

In Figure 3 it will be seen that the pick-up for the impact and static pressures are mounted'on a separate sleeve member to be inserted into the duct structure as indicated in Figure 3 at 80 or suitably secured to the existing duct structure on theinner periphery thereof. The pick-up de-. vice includes a first annular tube 81 havinga plurality of orifices 82 on the downstream side thereof which orifices are considerably small r than the inner dimensions of the tube and serve to provide an average of the static pressure around the inner periphery of the, duct structure. Connected to the tubular member 81 is a 'take-oit tube 85 which'is also of a larger diametrical dimension than the orifices 82 in the tube 81 The'take-oif stem 85 would" be connected to the conduit 76' as shown. in Figure 1. Positioned downstreamof the tube 81 is a secondtubul'ar member or 'sen'singflelement 90 having'an. annular assage therein and a plurality of orifices indicated at 91 oi the upstream surface thereof with a suitable channel member surroundin the orifices on the upstream-face of the tube to mount and position a filterindicated at 93 over the surface of the orifices. As in the tube 81, the

orifices 91 are considerably smaller than the inner dimensions of the tube or structure 96. Thestructure 90 also includes a takeeoflf tube 95 connected to the'tube 90 and having a dimension larger than the impact pressure orifices 91. The-filter 93 serves to prevent dirt and dust from clogging the impact pressure orifices and the distribution of the orifices about the member 90 would provide an' average impact pressure in the collector tube 95 which would be connected to the conduit leading to the relay'60 in Figure l. The tube is supported on the tube 81 by means of a plurality of wires or supporting members 97 through suitable attachment means such as welding'o'f soldering.

As was indicated in Figure 3, the velocity pick-up or sensing head may be mounted in its own sleeve with a suitablefiange 96 attached thereto to be positioned in theend portion 13 of the duct structure and suitably secured thereto or the tubular members 81 and 90 may be mounted within the structure independent of a sleeve through suitable means not shown. It will also be noted that the impact pressure tube is-of a smaller diametri'cal dimension and is'positioned downstream of the static lit a generally rectangular duct configuration. Here againthe apparatus is shown as mounted 'on a sleeve or supporting portion 100 having a flange 101 with a static pressure tube indicated as a generally rectangular form of tubular cross section 102 with the static pressure orifices on the downstream side thereof and the tubular member being secured to the support 106 through suitable means such as soldering. The tubular form also includes or hasvattached thereto a take-oft pipe 103. In thisembodiment, the impact pressure tube is a centrally located single tube mounted through supports indicated at 105- withithe tube 105 having'its extremity sealed by the supports 164 A pluralityof spaced orifices on the upstream side thereof communicate with the interior of the tubular portion 104 to which isattached the take-0d pipe 106 in a conventional manner. In this arrangement thesleeve 100 may be mounted through the flanges 101 to the duct structure or the apparatus may be mounted independently within the duct structure through suitable means not shown. In this arrangement the impact pressure sensing tube is located downstream of the static pressure tube and centrally thereof .to provide again a slight Venturi eifect andtake an average sampling of the impact pressures at the center of the duct structure;

The flow control means in the inlet portion 11 through its conduit 50 is connected to a relay means or controller indicated generally at 110 which unit is substantially the same as that disclosed schematically in the relay unit 60. The relay 110 has a case 111 divided by a plurality of diap'hragms 112, 113 and 114 to'provide two chambers between the diaphragms which are connected by a suitable rod 115 with the diaphragm 114 cooperating with a nozzle 116 at the extremity of the conduit 50 to control the pressure at the air conditioning medium within the chambers of the flow control means. The case 111 is vented at 120 and a spring 121 cooperates with the diaphragm 120 to move the same relative to the nozzle 116. In this unit the chamber formed by the diphragms 112, 113 is connected by means of the conduit 125 to'a static pressure sensor in the inlet portion of the duct structure upstream of the fiow'control means and the. chamber formed be tween the diaphragms 113 and 114 are connected by means of a conduit 126 to the impact pressure sensor. similarly positioned upstream of the flow control means in the duct portion 11. The area within the case 111 and between the wall of the case in the diaphragm J112'is connected by means of a conduit 130 to a thermostat indict ted schematic-ally or generally at 131, the thermostat to be located within the space to be air conditioned andresponding to room temperature thereof for the purpose or controlling the temperature of the air conditioning medium discharged'through theoutletportion 13 of the duct structure. Thermostat 131 is of bleed type which is provided with a source of controlling medium by means of a branchpas'sage connected to the conduit 50 on the downstream side of the restriction 51 and connected through a pressure regulator indicated generally at 142 attached to the case 111 ,ofjtherelay 110 and communicating withthe chamber between the diaphragm 112 and the wall of the caselll. The pressure regulator is convention'al inform utilizing a spring 145 acting against a diaphragm 146 to control a valve passage between the diaphragm and a portion ofthe case and allow a portion of the air conditioning medium to, flow into the above mentioned chamber to which the thermostat is connected to apply a pressure to this side or the diaphragm.

Thus the relay 110 includes a portion responsive to velocity of flow or flow through the inlet portion 11 of the duct structure which pressure differential acts against the spring 121 to control the flow from the nozzle 116 on the conduit 50 to vary the pressure applied to the diaphragms of the flow controlling means in the inlet portion 11 of the duct structure and hence the flow of air conditioning medium therethrough. Simultaneously the thermostat 131 will operate as a reset mechanism or a second controlling condition which will act on the diaphragm 112 to urge the diaphragm 114 against the nozzle 116 to control the positions of the flow controlling means in response to temperature of the space to be air conditioned. The pressure regulator 142 is included in this control branch to compensate for variations in pressure in the flow controlling medium.

In operation, the subject air conditioning and distributing apparatus is generally adapted to be connected to a double duct air conditioning system in which air conditioning medium in the form of tempered air of two different temperatures is conveyed from a central heating plant or heat exchangers along a duct work to be supplied to a plurality of units to be air conditioned. This improved duct structure with its associated valving means is adapted to be connected at its inlet portions respectively to the supply ducts of the air conditioning apparatus to proportion the amount of temperate air from each of the sources to a common outlet portion which is adapted to be connected to an individual space unit to be air conditioned. The valves or flow control means within the inlet portions of the duct structure are of the self-contained type made integral with or adapted to be assembled on existing duct structures. Generally the control apparatus responding to velocity of flow at one of the inlet portions and reset by temperature is adapted to be connected to the warm air supply and a portion of this warm air supply is utilized for operating the valve means and the associated control apparatus. The flow control means for the cold air duct or the opposite inlet portion is controlled by a relay which is operated in proportion to total flow through the outlet portion of the duct structure or the total flow into the space to be air conditioned. The improved sensing apparatus provides for taking an average of static and impact pressures within the duct portions where they are located to provide a resultant signal which is independent of turbulence or individual variations within the duct portions. In this manner a true and accurate control is obtained for a constant volume delivery of air to the space to be air conditioned and/or more accurate control is obtained as to the resultant temperature of the air to be supplied to the sapce to be air conditioned. Shown schematically in Figure 1 and associated withthe outlet portion of the duct structure is a noise filter 150 designed to eliminate or prevent the noise of turbulence of the air from becoming objectionable in the space to be air conditioned. This filter is of a conventional type and is shown in Figure 1 schematically for simplicity purposes.

In considering this invention it should be remembered that the present disclosure is intended to be illustrative only and the scope of the invention should be determined only by the appended claims.

I claim as my invention:

1. Valve apparatus including a Y-shaped duct structure the bifurcated portion of which is adaptedto be connected to a double duct air conditioning-system and the opposite extremity of which is adapted to be connected to a space to be air conditioned, 'a centrally located weir positioned in each of the bifurcated portions of said duct structure, diaphragm means positioned in said duct structure on either side of said weir for cooperation with said weir to close the passages through said duct structure to the opposite extremity thereof, an orifice positioned in each weir and connected through 'a passage to a chamber on the .OPPOsite side of said diaphragms from said weir,.-

valve means connected-to said passages of said orifice for each weir for venting said passages to the atmosphere, motive means for operating each of said valve means, means responsive to flow through one of said bifurcated portions of Y-shaped duct structure for controlling one of said motive means of said valve means associ ated with the diaphragms located in said one of said bifurcated portions of said duct structure, means responsive to the temperature of the space to be air conditioned for controlling co-jointly with said flow responsive means said one of said motive means, and means responsive to the total flow through the other extremity of said Y-shaped duct structure for controlling the motive means of the valve means associated with the diaphragms in the other of said bifurcated portions of said duct structure.

2. Valve apparatus including a Y-shaped duct structure having a bifurcated portion which is adapted to be connected to a double duct air conditioning system and an opposite extremity which is adapted to be connected to a space to be air conditioned, a centrally located double-faced weir positioned in each of the bifurcatedportions of said duct structure, apertures in said duct structure on either side of said double-faced weir, diaphragm means positioned over said apertures in said duct structure to cooperate with the respective faces of said weir, cover means positioned over said diaphragm means and secured to said duct structure securing said diaphragms in place and providing a variable chamber by means of which said diaphragms are made to cooperate with said weir to provide a flow control means through said bifurcated portions of said duct structure, an orifice positioned in each weir and connected through a passage to the chambers associated with said diaphragms to provide a self-contained means for operating the diaphragms and controlling the air flow means through the duct structure, valve means connected to the passages of each orifice for each weir for venting said passages to the atmosphere, motive means for operating each of said valve means, means responsive to flow through one of said flow control means for controlling one of said motive means of said valve means associated with the diaphragms of the flow control means, means responsive to temperature of the space to be air conditioned for controlling co-jointly with said flow responsive means said one of said motive means, and means responsive to total flow through the other extremity of said Y-shaped duct structure for controlling the motive means of the valve means associated with the flow control means in the other of said bifurcated portions of said duct structure.

3. Valve apparatus including a Y-shaped duct structure having a bifurcated portion which is adapted to be connected to a double duct air conditioning system and an opposite extremity which is adapted to be connected to a space to be air conditioned, a centrally located double-faced weir positioned in each of the bifurcated portions of said duct structure, apertures in said duct structure on either side of said double-faced weir, diaphragm means positioned over said apertures in said duct structure to cooperate with the respective faces of said weir, cover means positioned over said diaphragm means and secured to said duct structures securing said diaphragms in place and providing a variable chamber by means of which said diaphragms are made to cooperate with said Weir to provide a flow control means through saidbifurcated portions of said duct structure, an orifice positioned in each weir and connected through a passage to the chambers associated with said di-' aphragms to provide a self-contained means for operating the diaphragms and controlling the air fiow means through the duct structure, valve means connected to the passages of each orifice for each weir for venting said passages to the atmosphere, motive means for operating each of said val ve means, means responsive to the a ese o'ze,

velocity of flow of air conditioning medium through one of said flow control means in said Y-shaped duet structure for controlling one of said motive means of saidvalve'means associated with the diaphragms of said one of said flow control means, means responsive to the temperature of the space to be air conditioned for controlling co-jointly with said velocity responsive means said one of said motive means, and means responsive to total velocity flow through the other extremity of said Y-shaped duct structure for controlling the motive means of the valve means associated with the flow control means in the other of said bifurcated portions of said duct structure.

4. Valve apparatus including a Y-shaped duct structure having a bifurcated portion Which is adapted to be connected to a double duct air conditioning system and an opposite extremity which is adapted to be connected to a space to be air conditioned, a centrally located double-faced weir positioned in each of the bifurcated portions of said duct structure, apertures in said duct structure on either side of said double-faced weir, diaphragm means positioned over said apertures in said duct structure to cooperate with the respective faces of said weir, cover means positioned over said diaphragm means and secured to said duct structures securing said diaphragms in place and providing a variable chamber by means of which said diaphragms are made to cooperate with said weir to provide a flow control means through said bifurcated portions of said duct structure, an orifice positioned'in each weir and connected through a passage to the chambers associated with said diaphragms to provide a self-contained means for operating the diaphragms and controlling the air flow means through the duct structure, valve means connected to the passages of each orifice for each weir for venting said passages to the atmosphere, motive means for operating each of said valve means, pressure responsive means responsive to flow through one of said flow control means in said Y-shaped duct structure for controlling one of said motive means of said valve means associated with the di aphragms or" said one of said flow control means, means responsive to the temperature of the space to be air conditioned for controlling co-jointly with said flow responsive means said one of said motive means, and pressure responsive means responsive to total flow through the other extremity of said Y-shaped duct structure for controlling the motive means of the valve means associated with the flow control means in the other of said bifurcated portions of said duct structure.

5. In an air conditioning system, a duct structure having a pair of inlet portions connected to a common outlet portion the inlet portions being adapted to be connected respectively to a pair of ducts carrying two diiferent air conditioning mediums which are to be proportionally mixed and exhausted to a space to be air conditioned from the common outlet portion, flow controlling means positioned in each of said inlet portions and being formed by a centrally located weir positioned therein and a pair of flexible diaphragms located over apertures in said duct structure on opposite sides of said weir and cooperating with said weir,'cover meanspositioned over each of said diaphragms forming chambers with said di-aphragms, conduit means connected tocach weir and to said chambers for each of said flow controlling means to direct a portion of the flow of air conditioning medium to the chamber to urge the diaphragm against the weir and operate the flow controlling means, valve means for controlling the pressure of the air conditioning medium in the chamber to control the operation of the flow controlling means, motive means for operating said valve means for each of said flow controlling means, a first tubular member mounted in one inlet portion of said structure upstream of the flow con trol meanstherein and on theinner periphery of said duct structure having a plurality of'spaced orifices on the downstream side thereof and a take-off pipe connected to the'tubular member, a second tubular member located downstream of said first tubular member and upstream of said flow controlling-means, said second tubular member being centrally located within said duct structure and having a plurality of spaced orifices out-he upstream side thereof and a take-0E pipe connected to said second tubular member, means connecting said first and second takeoff pipes to said motive means of one of said flow control means for controlling the valve associated therewith in one of said inlet portions of said duct structure, a similar pair of first and second tubular members positioned in the outlet portion of said duct structure and including take-off pipes respectively connected to said motive means controlling the valve means associatedwith the other of said flow controlling in the other inlet portion of said duct structure, and means responsive to temperature of the space to be air conditioned connected to said first named valve means to simultaneously control the valve means associated therewith. v c

In an air conditioning system, a duct structure having a pair of inlet portions connected to a common outlet portion the inlet portions being adapted to be connected respectively to a pair of ducts. carrying two difierent air conditioningmediums which are to be proportionally mixed and exhausted to a space to be air conditioned from the common outlet portion, flow controlling means positioned in each of said inlet portions and being formed by a centrally located weir positioned therein and a pair of flexible diaphragms located over apertures in said duct structure onopp'osite sides of said weir and cooperating with said weir, cover means positioned over each of said diaphragms forming chambers with said diaphragms, an aperture in the upstream face of said weir connected to said chamber to direct a portion of the flow of air conditioning medium to said chamher to urge the diaphragms against thewe'ir and provide a self-contained actuator, valve means for controlling the pressure of the air conditioning medium in the chamber to control the operation of the flow controlling means, motive means for operating said valve means for each of said flow controlling means, a first tubular member mounted in one inlet portion of said duct structure upstream of the flow control means therein and on the inner periphery of said ductstrncture having a plurality of spaced orifices on the downstream side thereof and a take-ofl? pipe connected to the tubular member, a second tubular member located downstream of said first tubular member and upstream of said flow controlling means, said second tubular member being "centrally located within said duct structure and having a plurality of spaced orifices on the upstr'earn sidethereof and a take-01f pipe connected to said second tubular member, means connecting said 'first and second take-off pipes to said motive means of one of said flow control means for controlling the valve associated therewith in one of said inlet portions of said duct structures, a similar pair of first and second tubular members positioned in the outlet portion of said duct structure and including take-oif pipes respectively connected to said motive means controlling the valve means associated with the other of said flow controlling in the other inlet portion of said duct structure and pressure regulating means connected to said conduit for the aperture in said weir, and means responsive to the temperature of the space to be air conditioned connected to the pressure regulating means and connectedto said first named motive means to control simultaneously therewith the valve means associated therewith.

7. In an air conditioning system, a duct structure havlet portion the inlet .portions being adapted to be con nected respectively to a pair of dam carryin two dinerent air conditioning mediums which areito' bie' proportionally mixed and exhausted to a space to beair conditioned from the common outlet portion, flow controlling means positioned in each of said inlet portions and being formed by a centrally located weir positioned therein and a pair of flexible diaphragms located over apertures in said duct structure on opposite sides of said weir and cooperating with said weir, cover means positioned over each of said diaphragms forming chambers with said diaphragms, conduit means connected to each weir and to said chambers for each of said controlling means to direct a portion of the flow of air conditioning medium to the chamber to urge the diaphragm against the weir and operate the flow controlling means, valve means for controlling the pressure of the air conditioning medium in the chamber to control the operation of the flow controlling means, motive means for operating said valve means for each of said flow controlling means, a first flow sensor positioned in one of said inlet portions of said duct structure upstream of the How control means positioned therein and comprising a first tube having a plurality of static pressure orifices and a collector tube associated therewith and a second tube with a plurality of impact pressure orifices and a collector tube associated therewith, means connecting said impact and static pressure collector tubes to said motive means for operating the valve means associated therewith to control the flow control means positioned in said one of said inlet portions of said duct structure, a second flow responsive means positioned in the outlet portion of said duct structure and including a static pressure tube with a plurality of static pressure orifices and an impact pressure tube with a plurality of impact pressure orifices and associated collector tubes for impact and static pressure, means con necting the collector tubes of said second flow control sensor to the other of said motive means operating the valve means associated with the flow control means in the other of said inlet portions of said duct structure, and temperature responsive means positioned in the space to be air conditioned and connected to said first named motive means for adjusting the control point of said motive means.

8. In an air conditioning system, a duct structure having a pair of inlet portions connected to a common outlet portion the inlet portions being adapted to be connected respectively to a pair of ducts carrying two different air conditioning mediums which are to be proportionally mixed and exhausted to a space to be air conditioned from the common outlet portion, flow controlling means positioned in each of said inlet portions, and beingformed by a centrally located weir positioned therein and a pair of flexible diaphragms located over apertures in said duct structure on opposite sides of said weir and cooperating with said weir, cover means positioned over each of said diaphragms forming chambers with said diaphragms, conduit means connected to each weir and to said chambers for each of said flow controlling means to direct a portion of the flow of air conditioning medium to the chamber to urge the diaphragm against the weir and operate the flow controlling means, valve means for controlling the pressure of the air conditioning medium in the chamber to control the opera tion of the flow controlling means, motive means for operating said valve means for each of said flow controlling means, a first flow sensor positioned in one of said inlet portions of said duct structure upstream of the flow control means positioned therein and comprising a first tube having a plurality of static pressure orifices and a collector tube associated therewith and a second tube with a plurality of impact pressure orifices and a collector tube associated therewith, means connecting said impact and static pressure collector tubes to said motive means for operating the valve means associated therewith to control the flow control means positioned in said one of said inlet portions of said duct structure, a second flow responsive means positioned in the outlet portion of said duct structure and including a static pressure tube with a plurality of static pressure orifices and an impact pressure tube with a plurality of impact pressure orifices and associated collector tubes for impact and static pressure, means connecting the collector tubes of said second flow control sensor to the other of said motive means operating the valve means associated with the flow control means in the other of said inlet portions of said duct structure, pressure regulating means connected to a conduit means of the weir in said one of said inlet portions and supplying an auxiliary source of power, means responsive to the temperature space to be air conditioned connected to said pressure regulating means and said motive means for the flow sensor in said one of said inlet portions to control simultaneously with the flow responsive means the operation of the flow control means in said one of said inlet portions of said duct structure.

9. In an air conditioning system, a duct structure having a pair of inlet portions connected to a common outlet portion the inlet portions being adapted to be connected respectively to a pair of ducts carrying two different air conditioning mediums which are to be proportionally mixed and exhausted through said outlet portion to a space to be air conditioned, a flow control means positioned in each of said inlet portions of said duct structure, means for supplying a working pressure of the air conditioning medium from the inlet portions of said duct structure to said flow controlling means to actuate said flow controlling means and provide a selfcontained control, means sensing pressures in one of said inlet portions indicative of the rate of flow therethrough, means operated by the pressures sensed in said one of said inlet portions to control the pressure of the air conditioning medium supplied to the associated flow control means, means responsive to the temperature of the space to be air conditioned to adjust the control point of the pressure operated means associated with said one of said flow control means, means in the outlet portion of said duct structures indicative of total rate of flow therethrough, and means operated by the pressures sensed in said outlet portions of said duct structure to control the working pressure of the air conditioned medium supplied to the other of said flow controlling means to control the operation of the same. r

10. In an air conditioning system, a Y-shaped duct structure having a pair of inlet portions connected to a common outlet portion the inlet portions being adapted to be connected respectively to a pair of ducts carrying two difierent air conditioning mediums which are to be proportionally mixed and exhausted through said outlet portion to a space to be air conditioned, a flow control means positioned in each of said inlet portions of said duct structure, said flow controlling means including a centrally located weir in each of the inlet portions of said duct structure and a pair of diaphragms located in aperture in the duct structures on opposite sides of the weir, means for supplying a working pressure from the flow controlling medium to act on the diaphragms of the flow controlling means to provide a selfcontained controller, means sensing pressures in one of said inlet portions indicative of the rate of flow therethrough, means operated by the pressures sensed in said one of said inlet portions to control the pressure of the air conditioning medium supplied to the associated flow control means, means responsive to the temperature of the space to be air conditioned to adjust the control point of the pressure operated means associated with said one of said flow control means, means in the outlet portion of said duct structures indicative of total rate of flow theretbrough, and means operated by the pressures sensed in said outlet portions of said duct structure to control the working pressure of the air conditioned anemone '11 medium supplied to the other of said flow controlling means to control the operation of the same.

11. In a self-contained, valve 'for, anair conditioning medium, a duct structure, a centrally located weir in said duct structure and attached thereto, apertures above and below said weir in said duct structure, a pair "of diaphragms positioned over said apertures, cover means positioned over said diaphrag-ms defining a variable chamber therebetween, said diaphraglns coopera't ingwith said weir to control the flow of said air conditioning medium through said'd'uct structure, conduit means positioned in said weir and connected to said variable chambers, and means conneetedto said conduit means and adapted to vent said conduit means to the atmosphere,

12. In a self-contained valve for an air conditioning medium, a duct. structure, a cenu'ally' loo'ated Weir in said duct structure and attached thereto, apertures above and below said weir in said duct structure, a of diaphragms positioned over said apertures, cover means positioned over saiddiaphragms securing the same to said duct structure and defining with said diaphragm variable chambers, said diaphragms cooperating with said weir to control the flow of said air conditioning medium through said duct structure, conduit means positioned in sai'c l weir and connected to said variable chambers, and means connected to said conduit means and adapted to vent said conduit means to the atmosphere.

13. In a self contained valve for an air conditioning medium, a duct structure having an inlet and outlet, a centrally located double faced weir positioned in said duct structure and defining said inlet and outlet, aperture means in said duct structure on either side of saiddouble faced weir, diaphragm means positioned over said apertures in said duct structure to cooperatew ith the faces of said weir to control the flow of air conditioning medium through said duct structure, cover means positioned over said diaphragm means and secured to said duct structure securing said diaphragm in said place and providing a variable chamber by means of which said diaphragms are made to cooperate with said weir, an orifice positioned in said Weir and connected through a passage to said chambers associated with said'diaphrag'ins to provide a self-contained source for operating said diaphragms and controlling the flow of air-conditioning medium therethrough, and valve means connected to the passages of the orifice for venting the passage-to the atmosphere. 7

14. In an air conditioning system, a duct structure for carrying an air conditioning medium, flow controlling means positioned in said duct structure to vary the flow of said air conditioning medium thereth-r'ough, means for controlling said flow controlling means i'n'said duet structure, a flow sensor positioned in said duct structure upstream of said fiow control means and compr-i'singa first tubular member mounted on the inner periphery of the duct structure and having a plurality of spaced orifices on the downstream side thereof and a take-0dr point con"- References Cited in the file of this patent UNITED STATES PATENTS 1,702,274 Schmidt Feb. 19, 1929 1,934,713 Hughes r. Nov. 14, 1933 2,584,420 Branson Feb. 5, 1952 2,705,595 Carlson et al. Apr. 5, 1955 

